Rot damage constitutes a great problem in connection with wooden windows of previously known type. Rot damage on wooden windows gives rise to considerable costs for house-owners. A basic reason for the problem is that the frames of the windows are made of wood pieces the characteristics and fibre-orientation of which are, in all essentials, uncontrolled. Thus, the window manufacturer buys board blanks the location of extraction of which in the original log may lie just anywhere. In some cases, the board may be extracted from the outer sap of the log and in other cases extracted from the central heartwood. The window manufacturer totally lacks control of the orientation of the annual rings. Sometimes the presence of heartwood in the individual frame piece may be orientated inwards in the frame and sometimes outwards. The turning of the wooden material is above all guided by the presence of possible knots, which are orientated towards the hidden side of the frame. Usually possible knots are drilled out and replaced by knotfree wooden plugs which are glued without any particular selection in comparison to the surrounding frame wood and external weather exposure respectively. In the traditional sawing of logs, the log is split or divided by means of a plurality of parallel sawing cuts, which, particularly in case of small dimension logs, entails that the annual rings of the wood will be mainly orientated lying in the surface which is turned outwards in the finished frame piece. By the fact that the bulking susceptibility of the wood is larger in the tangential direction (in practice about 7%) than in the radial direction (about 4%), paint or other surface treatment layers outside the individual frame piece are exposed to large, alternating shrinkage and elongation stresses which lead to crack formations in the protecting paint layer as well as in the proper surface wood. The rot problem is particularly marked in the bottom piece of the frame and the lower parts of the side pieces of the frame, which in practice relatively fast (from 8 to 15 years) tend to putrefy up to a height of about 20 cm as a consequence of water penetration in cracks and capillary suction of water from the lower ends of the side pieces, which ends are connected to the bottom piece of the frame. Another disadvantage of traditional frames is that all of the frame pieces mainly are of a rectangular cross section shape. This cross section shape means that the viewing or panoramic angle for an observer being indoors is limited by the outer edges of the frame pieces facing the centre of the frame rather than the inner edges which are closer to the observer. Therefore, for a given frame size, the panoramic angle will be relatively small.